Usual varied suggestions - some correct some not.
DONT use Optiglanz - this is for plain stainless steel pipes.
If you want pipes clean and shiny you have to polish them from birth!
If you've left it for thousands of miles try a very fine wire wool with Autosol.
It will take a while but persist.
When blue has gone, polish again with Autosol (I use an old sock wrapped twice around the pipe and an old toothbrush) and polish.
Then you need Brilliant (Chrome/Hot environment/Nickel Polish) Cleaner):
http://www.briliant.biz/products.asp?CategoryId=1
Polish with this and after riding it will still blue a little but not as bad as before and it will be easier to polish up next time.
Chrome needs cleaning otherwise it, like stainles steel will oxidise and after a whlie go rusty, especially if a nick penetrates the chrome skin.
Picture shows my GSA June 2010 with 6240 miles on clock and still looking good.
Safe riding,
Mike